The eye may be infected from external sources or through intraocular invasion of micro-organisms that are carried by the blood stream. [1] External bacterial infections of the eye are usually localized but may frequently spread to other tissues. The eyelid and conjunctiva have a normal microbial flora controlled by its own mechanism and by the host. Modification of this normal flora contributes to ocular infections such as blepharitis, conjunctivitis, canaliculitis, orbital cellulitis, endophthalmitis, etc. [1],[2],[3],[4],[5] Timely institution of appropriate therapy must be initiated to control the infections and thereby minimize ocular morbidity. If they are not treated promptly, it may lead to sight threatening condition. For specific antibacterial treatment, isolation and identification of bacterial pathogens along with antibiotic susceptibility spectrum is essential.

Diabetic retinopathy (DR) is an important complication of diabetes and the second most common cause of certifiable blindness in the working age population.1 It is thought to develop following compromise of the retinal microvascular circulation and can ultimately threaten sight. Early detection through screening can help preserve vision.The works of Klein et al published in 1984 gave some of the first estimates for prevalence and natural progression of DR in a large screening population.2, 3 Their study population were individuals diagnosed with diabetes in Wisconsin USA who were involved in their innovative screening programme. Patients were divided into those under 30 years of age at diagnosis of diabetes and on insulin (group 1) and those over 30 years of age at diagnosis either on insulin or on tablet treatment (group 2). Group 1 is likely to be predominantly, but perhaps not exclusively, type 1 diabetes mellitus (T1DM). The overall prevalence for DR and proliferative diabetic retinopathy (PDR) in Group 1 were 70.7% and 25.7% respectively. Disease duration was identified as a significant risk factor for severe disease with rates of PDR increasing from 1.2% in patients with T1DM for less than 10 years to 67% in those diagnosed with diabetes for 35 years or more.2

The bacterial etiology and their susceptibility as well as resistance patterns may vary with geographic location according to the local population.[6],[7]Streptococcus pneumoniae was reported to be the predominant corneal pathogen in Tiruchirapalli [8] and Madurai, [9]whereas in Coimbatore it was Pseudomonas aeruginosa.[10]Ps. aeruginosa was reported to be the most common bacterial pathogen causing postoperative endophthalmitis in Chennai, [11] whereas in Madurai it was Nocardiasp. [12] Similarly, there was a variation in the in vitro efficacy of antibacterial agents against bacterial pathogens causing ocular infections according to the local population. For instance, ciprofloxacin showed higher sensitivity against keratitis pathogens in Tirunelveli (90%) [13] than in Hyderabad (69.3%). [14]

Although the treatment of diabetes has changed significantly since these seminal papers, current prevalence studies for DR in T1DM alone are scarce. There is a particular paucity of data from the UK in global systematic reviews.4, 5 In 2002, Younis et al published the first major UK study of DR prevalence in T1DM individuals at entry into a retinal screening programme.6 In 2015, Thomas et al also reported the prevalence of DR in a large community based screening programme.7

Whilst their studies also found a strong association between duration of disease and severe DR, the relationship between diabetes duration with diabetic maculopathy and PDR specifically were not investigated. Moreover data on modifiable systemic risk factors was not included.

The purpose of this study was to identify the etiology, incidence and prevalence of ocular bacterial infections, and to assess the in vitro susceptibility of these ocular bacterial isolates to commonly used antibiotics.

This study aims to provide a contemporary estimate of the prevalence of DR of all grades, in a UK cohort of T1DM Caucasian patients using data collected by the Southampton Diabetic Eye Screening Programme. Rather than making any assumptions based on age at diagnosis, these patients were diagnosed with T1DM by a consultant diabetologist.8 A further aim of this study was to investigate the associations between PDR and maculopathy with potential risk factors: age, gender, duration of disease, blood pressure, cholesterol, urine albumin to creatinine ratio (ACR), glycaemic control and smoking history.

Example

Burden of asymptomatic malaria among a tribal population in a forested village of central India: a hidden challenge for malaria control in India.

Public Health. 2017;147:92-97.

Introduction

Current knowledge about malaria

In India, the national programme reported 1.1 million new cases of malaria and 561 deaths in 2014. Two protozoan parasites—Plasmodium vivaxandPlasmodium falciparum—lead to malaria deaths with a ratio of approximately 1:1.9. The state of Chhattisgarh, representing approximately 2% of the population of India, is a malaria-endemic state, accounting for nearly 12% of all reported cases.P. falciparumis the predominant (84%) parasite species, followed byP. vivax. There are also sporadic reports ofPlasmodium malariaeinfections from southern districts (Dantewada, Bastar and Kondagaon), although these account for <1% of the cases in the district. There were 53 reported deaths due to malaria in Chhattisgarh state in 2014.1

Current knowledge about Burden of asymptomatic malaria among a tribal population in a forested village of central India:

The southern part of Chhattisgarh comprises seven administrative districts, namely Bijapur, Sukma, Dantewada, Bastar, Kondagaon, Narayanpur and Kanker (total population three million). These districts are mainly forested and inhabited by predominantly native tribal populations and have remained endemic for malaria since the inception of the national malaria control programme. In 2014, the annual parasite incidence (API, cases/1000 population/year) was 8.4 in one district (Kanker) and ranged from 10.4 to 53.6 in the other six districts. These districts, including Kondagaon, contributed 58.4% (total positive count 68,505/117,292) of all cases of malaria reported in Chhattisgarh state in 2014. Despite regular malaria control activities supported by a near-adequate health infrastructure, fortnightly active fever surveillance and treatment of malaria infection, indoor residual spraying with synthetic pyrethroids (coverage rate 44–88%) and distribution of long-lasting insecticidal nets (user rate 35–65%), there is persistent transmission of malaria in this area.2The persistence of the infections could be due to asymptomatic cases. Asymptomatic (subclinical) malaria refers to the presence of malaria parasites in the blood without symptoms, usually provides a reservoir for transmission, and is an antecedent to symptomatic malaria.3Previously, it was believed that only areas of high endemicity are at risk of subclinical infection, but more recent studies from other malaria-endemic regions (e.g. countries in Africa) have observed that communities living in low-transmission areas are also at the risk of asymptomatic parasitaemia.4In low-transmission areas, submicroscopic carriers can become the source of approximately 20–50% of all transmission.5The presence of a large number of asymptomatic carriers in a population is a challenge and places an additional burden on malaria control programmes.6

Gap in knowledge about Burden of asymptomatic malaria among a tribal population in a forested village of central India:

In India, studies in malaria-endemic areas have shown inconsistent findings in terms of the presence of asymptomatic malaria in the region, especially in tribal populations of Maharashtra, West Bengal and Assam.3,7,8,9,10Seasonal transmission is another factor that influences the prevalence of subclinical parasitaemia in the community.8

Our study design

Few published data on the burden of asymptomatic malaria parasitaemia are available from Chhattisgarh state. A cross-sectional survey carried out in 47 villages of Keshkal subdistrict of Kondagaon district in 2013 showed a high prevalence (slide positivity rate [SPR] 27.6%) of malaria in Randha village, and this was very high compared with the data provided by the state health department (10.3%), with a reported API of 3.4. A likely explanation for the disparity in reported cases is the presence of asymptomatic cases that may not have been captured through routine fever surveillance. Thus, reported incidence would underestimate the burden of malaria in the population. A correct estimate of symptomatic and asymptomatic cases is required to plan an effective malaria control programme. As such, this study was undertaken in 2014 to estimate the burden of asymptomatic malaria in a tribal population residing in Randha village.